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Flexibility (Testing and Training)

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Outline

Definitions of Flexibility Warm up vs Stretching Factors that influence Range Of Motion (ROM) Physiology and Biomechanics of Flexibility Assessment of Flexibility Benefits of Flexibility Flexibility program variables

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Definitions of Flexibility “ability to be bent, pliable” The New Shorter Oxford

English Dictionary (1993) Functional ability of a joint to move through its full

range of motion (ROM) (ACSM 2010) Functional ability - movement without incurring pain or a

limit to performance “The ability of a joint to move through its full range of

motion” (Brooks et al. 2000). There is little agreement about the definition of “normal”

flexibility. Optimum flexibility is hard to assess, and varies with

sport. More ROM is not necessarily better. Inadequate flexibility can decrease performance of

activities of daily living as well as some sports.

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Further Definitions

Flexibility refers to the extensibility of periarticular tissues to allow normal or physiological motion.

Laxity refers to the stability of a joint (Saal, 1987). Excessive joint laxity can be the result of

injury or heredity condition. Hypermobility refers to a range of motion in

excess of the accepted normal motion in most of the joints (Alter, 1996).

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Types of Flexibility

Static flexibility: ROM about a joint with no emphasis on speed.

Ballistic flexibility: usually associated with bobbing or bouncing motion.

Dynamic (functional) flexibility: ability to use ROM in the performance of a physical activity.

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Warm up Warm up prepares athletes for training or competition

May reduce the risk of injury and improve performance Increase muscle temperature, core temperature, and blood flow Impact on performance;

Faster muscle contraction and relaxation Increased rate of force development Inc muscle strength and power Lowers viscosity of muscle Improved O2 delivery (Bohr effect - temperature) Increased blood flow to active muscle Increased rate of metabolic reactions

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Components of a Warm up Warm up should be gradually progressive without causing

fatigue General - 5 to 10 minutes low intensity

My be sport specific (jogging / ball dribbling) Raise HR, ventilation, blood flow, deep muscle temperature and

reduce viscosity Specific - 10 minutes

Dynamic stretching (mobility drills) - sport specific movements (examples near end of lecture)

Progressively increase intensity - sprint drills, jumping High intensity dynamic exercises may facilitate subsequent

performance Static Stretching in warm up may decrease subsequent

performance Decreased force, power, running speed, reaction and movement

time, endurance

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Factors that Influence ROM Range of Motion (ROM) is joint specific, and results from

a combination of factors; including adequate warm-up Structure of Joint - (47%)

Determines degree of freedom of movement Hinge vs ball and socket joint

Rigidity of Ligaments (10%) Help stabilize and protect joints from excessive motion during

dynamic movements Restrict ROM and offer support at end of ROM

Extensibility of periarticular tissues - muscle and tendon (41%) Component that can be modified most significantly and

influenced by flexibility training Length of muscle and level of neurological innervation in

muscle being stretched

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Other influences on Flexibility Nervous system activity

Sudden stretch of a muscle stimulates muscle spindle and reflex contraction

Important for proprioception and controlling muscle length

Slow static stretches, spindle activity increases for about 10 sec then diminishes greatly This can also help alleviate muscle cramps

Intracapsular structures articular cartilage and synovial membranes facilitate

smoothness of movement while maintaining integrity of joint

Soft tissue compression of soft tissue by adjacent segments

contributes to termination of ROM Eg obese or very heavy musculature

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Limits due to Muscle Structure

Contractile Components of Muscle Sacromere (S) resting length 2.30mm Maximum extensibility 3.50mm (150%) Hence increased extensibility occurs by an increase in

the # of sarcomeres in series

Improper Muscle Balance Stretch short muscle (flexibility assessment) Strengthen weak muscle (strength assessment)

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Total Length-Tension Curve

Text Fig.3-18

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Limits due to Connective Tissue Connective tissue surrounds muscle fibers (fascia), and in

a major component of tendons and ligaments Collagen - strong and flexible but resist stretching Elastin - thin with high degree of elasticity

ability to stretch and recoil

Stress / Strain curves Fig 54.1 ACSM Linear - elastic region - will return to original shape non linear - plastic deformation and repair by fibroblasts

Sustained stretch of 30-90 seconds in necessary to get beyond elastic recoil properties of skeletal muscle and stimulate fiber reorganization

Goal of flexibility training program is to induce gradual deformation of connective tissue - stimulate repair and greater ROM

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Limits due to Connective Tissue Aging

Joints become less stable and less mobile Degradation of collagen, joint surface, and

decreased viscosity of synovial fluid increases collagens diameter and more collagen

cross-links Stiffness and inflexibility common with aging Sometimes difficult to separate aging from wear

and tear to joints Flexibility training can induce remarkable

improvements in aged population if no permanent damage to joint structure has occurred

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Assessment of Flexibility Measurement made visually or with special instrumentation Utilize active or passive movement of subject Precision in assessment techniques enhances both accuracy

and reliability Proper identification of landmarks Consistency in the inclusion or exclusion of a warm-up is important

for reliability Starting position and body position for measurements

Visual assessment (qualitative) - inaccurate for both spinal and extremity evaluation but useful for fitness screening, group evaluation and field testing - we

will do several visual assessments Degree of completion of assessment in standard position -

see lab manual Eg - Finger tips touching (or not) with combined bilateral

rotation of shoulders and elbow flexion

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Quantitative Assessment of Flexibility Measurement Devices Indirect - linear - sit and reach apparatus,

anthropometer, tape measure Direct - ROM in degrees - Goniometer /

Leighton Flexometer Goniometer is inexpensive and portable Kin 142 no longer uses Flexometer

We will perform one measurement with Flexometer for familiarity and one with Goniometer for review

Dynamic Flexibility can be measured with stop motion video with reflective markers on bony landmarks Similar to motion capture for video games and animation

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Quantitative Measurements Eg. Sit-reach (modified by Hoeger) - accounts

for influence of length of body segments necessary when doing indirect measures First measure taken with back touching wall Second measurement with truck flexion Difference provides data for comparison

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Benefits of Flexibility Training Increased physical performance Decreased risk of injury (but not due to inclusion as

part of a warm-up) Increased blood supply and nutrients to joint

structure Increased quality and quantity of joint synovial fluid Increased muscular coordination Improved muscular balance, posture and postural

awareness Decreased muscle viscosity, causing contractions to

be easier and smoother

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Benefits of Flexibility (cont)

Reduced muscular soreness Promotion of relaxation (reduced muscular tension

and cramps) Decreased risk of low back pain Reduced stress and tension Increased enjoyment Promotes self-discipline Unification of body, mind and spirit (e.g. Yoga) Improves ease and efficiency of movement Increased Range of Motion Improves skill in sport

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Reasons why stretching before exercise may not prevent injury

An increase in muscle compliance may cause tissues to rupture more easily.

Stretching before exercise will have no effect for activities where excessive muscle length is not an issue.

Stretching will not affect muscle compliance during eccentric activity, where most strains are believed to occur.

Stretching can produce damage at the cytoskeleton level.

Stretching appears to mask muscle pain in humans.

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Who should not Stretch? Everyone can learn to stretch Caution for people who have naturally

excessive ROM - should not stretch in extremes of ROM as joint stability should be maintained

Recent push to certify Yoga instructors locally, reduce incidence of injury to clients

Pregnancy - hormone relaxant - softens ligaments and connective tissue especially in pelvis - excessive stretching can lead to hypermobility of low back

Table 54.2, 54.3 ACSM

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Flexibility Training Program Athletes should stretch following practice or as a

separate session (after sufficient warm up) Muscle is warm, collagen is elastic which allow greater

stretch May decrease muscle soreness

Training Program A planned, deliberate, and regular program of

exercises that can permanently and progressively increase the useable range of motion of a joint or set of joints over a period of time (Corbin and Noble, 1980).

Stretching recommended after sitting or standing for long periods - helps prevents discomfort (not enough to count as a training program)

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Duration and Frequency Variable opinions Duration

Beaulieu - 10-15 secs - progress to 45-60 secs over 4-5 weeks

Anderson - 10-30 sec easy; 10-30 sec developmental stretch

ACSM 10-30 seconds - but emphasize that connective tissue deformation and neuro-inhibitory effects require 30-90 seconds to effect tissue change and relaxation

Yoga - variable - 45-90 seconds Frequency

Beaulieu - 2-3 times / week Yoga - daily for 30-45 minutes - relaxation

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Controversy Optimum flexibility

sport specific? Types of stretching

Safety vs effectiveness Static vs dynamic stretching and

performance Dangerous stretches

Cautions in some guides, recommended in others?

Stretching during warm-up and cool-down Is it enough to effect changes in flexibility? Does it have an impact on injury or muscle

soreness?

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Ballistic Stretching

Advantages Development of

dynamic flexibility Effectiveness Team camaraderie Interest

Disadvantages Inadequate tissue

adaptation

Soreness and injury

Initiation of stretch reflex

Inadequate neurological adaptation

Disadvantages outweigh advantages

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Static Stretching Advantages Historical preference Effective and optimal Decrease possibility of

exceeding normal ROM

Less energy Less muscle soreness Recommended as

advantages outweigh disadvantages - especially for general population

Disadvantages Boring May overly dominate routine

due to time needed Allows body to cool during

warm up Principle of specificity -

effectiveness for improving dynamic flexibility?

Increase chance of injury by reducing amplitude of stretch reflex?

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Dynamic Stretching(mobility drills)

Advantages Focused on sport

specific movement Development of

dynamic flexibility Increases temperature Muscle is active Team camaraderie Interest Avoids bouncing and is

more controlled than ballistic stretching

Disadvantages Inadequate tissue

adaptation (ROM)

Soreness after first sessions

Inadequate neurological adaptation

advantages outweigh disadvantages

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Dynamic Stretching(mobility drills)

Preferred method of stretching during warm up Actively moving joint through ROM required for sport Observe sport specific movement patterns, and select

exercises that mimic those patterns Build progressively through each exercise

Speed and ROM Perform under control

ROM often less than what could be achieved with ballistic type movements

Do not accelerate limb to end of ROM

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Dynamic Stretching

STRAIGHT-LEG MARCH

(for the hamstrings and gluteus muscles)

Kick one leg straight out in front of you, with your toes flexed toward the sky. Reach your opposite arm to the upturned toes. Drop the leg and repeat with the opposite limbs. Continue the sequence for at least six or seven repetitions.

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SCORPION

(for the lower back, hip flexors and gluteus muscles)

Lie on your stomach, with your arms outstretched and your feet flexed so that only your toes are touching the ground. Kick your right foot toward your left arm, then kick your leftfoot toward your right arm. Since this is an advanced exercise, begin slowly, and repeat up to 12 times.

Dynamic Stretching

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HANDWALKS

(for the shoulders, core muscles, and hamstrings)

Stand straight, with your legs together. Bend over until both hands are flat on the ground. “Walk” with your hands forward until your back is almost extended. Keeping your legs straight, inch your feet toward your hands, then walk your hands forward again. Repeat five or six times. G.R.

Dynamic Stretching

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Additional Classifications Passive stretching - partner or stretching machine

provides external force Active Stretching - person stretching provides force Proprioceptive Neuromuscular Facilitation

contract muscle prior to stretch- 6 sec contraction; 10-30 sec stretch (Contract - Relax) Autogenic inhibition Golgi tendon organ and muscle spindle relaxation

Some also coincide stretch with contraction of agonist (ms opposite one being stretched) (Contract - Relax (Agonist Contract)) Reciprocal inhibition

Increased range of motion over static stretching More motivation required - beneficial to have knowledgeable

partner More time Increase pain and soreness and injury?

39NSCA - Essentials of Strength Training and Conditioning 2008